Blowouts are holes in pipes/tubes generally caused by foreign material in an extrudate, which forms the pipes/tubes, creating a weak or open area during a period of stretching and pulling as the extrudate enters the vacuum tank water bath before the extrudate cools off to finally the pipes/tubes.
Blowouts can be small micro perforations or huge holes that will actually rupture the pipes/tubes and stop the production line. The large holes that shut down the line are easy to detect, they are right at the tube break off point. The micro perforations are more difficult to find as they may simply run through the line undetected. A customer in the field may find them when the customer wants to carry out an irrigation project and turns the water on. Many blowouts detected at that time often manifest either as a geyser or a flooded pool. If the pipes/tubes are buried, as is often the case it is a long job digging in the mud to locate and repair every place where a blowout occurred. Since there is seldom a single occurrence of a blowout, the field could be littered with them, creating a tremendous amount of work for the customer, and a warranty nightmare for the manufacturer of the pipes/tubes.